Packer assemblies can be used in a wellbore to separate the wellbore into one or more zones. A packer assembly can include a packer element capable of providing an annular seal between a tubing string and a casing string, a slip that can retain the packer assembly in a position by gripping the casing string, a wedge that supports the slip, and a mandrel that provides support to the assembly.
Initially, the slip can be positioned closer to the mandrel such that it is unsupported by the wedge to facilitate running the packer assembly downhole. In a set or operation position, or otherwise after running the packer assembly downhole, the wedge supports the slip toward an inner diameter of the casing string. The slip can grip the inner wall of the casing string to retain the packer assembly in position.
It can be desirable to remove a packer assembly from the wellbore. A packer assembly can be removed after the wedge unsupports the slip. Various techniques have been developed to allow the wedge to unsupport the slip. The techniques include modifying a slip tooth angle and providing a collapsible wedge.
The slip tooth angle can be modified such that a passive angle of the tooth matches an angle on the wedge to allow the slip to be pulled off the wedge easier. Modifying the slip tooth angle, however, can decrease the load bearing capability of the slip and wedge and can result in damage to the casing. It can also result in debris being introduced downhole due to shearing that may be needed to release the wedge from the slip. A collapsible wedge can be made from a material that is not rigid or can include grooves that allow it to collapse downhole to release from supporting the slip. A collapsible wedge, however, may collapse prior to a desired time or debris can settle around the wedge, preventing collapse.
Other techniques include pulling the slip from the wedge, which can result in debris due to sheared metal and can be difficult in view of the outward force applied to the slip by the wedge.
Therefore, packer assemblies are desirable that can provide sufficient load bearing performance and that can be removable from the bore.